class Circle {
    double radius;

    public Circle(double radius) {
        this.radius = radius;
    }

    public void showPerimeter() {
        double perimeter = 2 * Math.PI * radius;
        System.out.printf("周长: %.2f\n", perimeter);
    }

    public void showArea() {
        double area = Math.PI * radius * radius;
        System.out.printf("面积: %.2f\n", area);
    }
}
